Optical fiber connection component, optical fiber connection structure, and optical fiber connection method

ABSTRACT

An optical fiber connection component which is easy to adjust the distance between the optical fiber ends before connection, hardly damages the optical fiber during transportation or connection, and saves the number of parts and the cost, and a method for connecting optical fibers by using this component. The optical fiber connection component used for the optical fiber connection method consists of a connection member having one or more optical fiber through-holes provided with guides for rodlike coupling member at or near both side ends, rodlike coupling members, and a plug having through-holes for rodlike coupling members. The connection member is arranged in the plug slidably with the rodlike coupling member inserted in the plug. Two such optical fiber connection components are opposed to the optical fiber inserted in the through-hole to butt the through-holes of both the connection members against each other. Both the connection members are slid in the direction of the center axis of the optical fiber along the rodlike coupling member guided by the guide, so that the optical fibers are jointed in the through-hole of one connection member.

TECHNICAL FIELD

The present invention relates to an optical fiber connection component,an optical fiber connection structure and an optical fiber connectionmethod, and in particular to an optical fiber connection componentcapable of connecting collectively a number of optical fibers ofmulti-core optical fibers, an optical fiber connection structure usingsaid components and a method for connecting optical fibers.

BACKGROUND ART

In optical connection between a plurality of optical elements in anoptical circuit package, or optical connection between optical fibersled out of a plurality of optical circuit packages or optical circuitdevices on which an optical circuit package has been mounted, an opticalconnector or mechanical splicer is generally installed between ends ofoptical fibers led out of optical elements, optical circuit packages,optical circuit devices and/or the like to connect the optical fibers,or the optical fibers are mutually connected by fusing connection.

However, the current optical connector requires PC (physical contact)connection for connecting the optical fibers. For reasons of that, it isnecessary to insert and fix the optical fibers into a ferrule made ofzirconia, glass, ceramic or the like and then polish the optical fibers.Therefore, a process for connecting the optical fibers is considerablycomplicated, and it takes a long time for the polishing step.

On the other hand, the connection by the mechanical splicer in which nopolishing step is required and the fusing connection requirespositioning the optical fibers, whose claddings have been exposed, in aV-shaped groove or within a capillary. In such a case, there has been apossibility that the claddings of the optical fibers may be damaged. Inparticular, when the optical fibers are positioned within a glasscapillary as described in Japanese Patent Application Laid-Open No.160564/1999, the claddings of the optical fibers have come into contactwith the capillary, and so there is a high possibility that ends of thecladdings of the optical fibers may be damaged. Another problem is thatthe connecting operation takes a long time and it causes a poor yieldrate.

The above publication and Japanese Patent Application Laid-Open No.264914/1999 show that a slot is provided in a capillary to fill a jointbetween the optical fibers with an adhesive or refractive index matchingagent. In such a case, the mechanical strength of the capillary becomesvery weak due to the provision of the slot, and the slot portion may bebroken during a connecting operation.

In the prior multi-fiber connectors, it becomes difficult to align theoptical fibers to each other as the number of optical fibers increases.Because the distance between the optical fibers and through-holes intowhich guide pins are inserted for alignment increases and it causes alarge errors on positioning. Further, when some ferrules have adifferent thermal expansion coefficient to each other, there is apossibility that the relative position of the holes into which opticalfibers are inserted shifts depending on environmental changes, therebyincreasing an optical loss.

As a method for solving the above-mentioned problems, it has beenproposed in Japanese Patent Application No. 2002-053484 that two opticalfibers are connected by providing two connecting members having each athrough-hole, into which an optical fiber has been inserted, bringingthem face to face with each other, and sliding then the connectingmembers. However, since this method does not use a member for keepingthe position of the connecting members holding the optical fibers, it isimpossible to keep distances between the ends of optical fibers to beconnected equal, and so it is necessary to adjust the distance for everyconnection between pairs of optical fibers. Moreover, upon carrying theconnecting members provided each with an optical fiber or connectingthem, discrepancy in position is caused between the center axis of theoptical fiber and the axis of the through-hole of the connecting member.Accordingly, there is a possibility that the optical fibers are damagedwhen the connecting members are slid to the optical fibers, whichreduces the handling workability of the connecting members underconnecting operation. Still more, in this method, an aligning member anda fixing member are used for aligning and fixing the connecting members.Therefore, there is a possibility of increasing cost because of usingmany parts. In addition, since parts for connection are not unified, theconnection process becomes complicated. No proposal is shown as anoptical fiber connection component to unify some parts.

The present invention has been completed for the purpose of solving theabove problems in the prior arts. An object of the present invention isto provide an optical fiber connection component which is easy to adjustthe distance between the optical fiber ends upon aligning the opticalfibers and, particularly, those coats of which have been removed, incase of connecting optical fibers led out of the edges of opticalelements, optical circuit packages, optical circuit devices, etc., andwhich hardly damages the optical fibers during carrying or connection,and saves the number of parts and the cost. Another object of thepresent invention is to provide an optical fiber connecting method usingsaid optical fiber connection components, and to provide an opticalfiber connection structure formed by said method.

DISCLOSURE OF THE INVENTION

An optical fiber connection component according to the present inventioncomprises a connection member having one or a plurality of through-holesfor optical fibers provided with guides for rodlike coupling member ator near both side edges, rodlike coupling members, and a turned squareU-shaped plug having a through-hole(s) or a groove(s) for inserting anoptical fiber(s) and guide holes for rodlike coupling members on thebottom of the concavity of square U-shape, wherein said connectionmember is arranged slidably in the plug by being installed in theconcavity of square U-shape of said plug by means of the rodlikecoupling member inserted in said plug.

In the present invention, the guide may have a form of through-hole orgroove. The rodlike coupling member is preferred to be cylindrical. Inthe present invention, two or more of the above-mentioned connectionmembers may be installed in the plug. Further, the plug to be used mayhave one or more through-holes or grooves for inserting optical fibers.

An optical fiber connecting method according to the present inventioncomprises providing the above-mentioned two optical fiber connectioncomponents, inserting optical fibers into through-holes of theconnection members respectively, opposing the connection members of saidtwo optical fiber connection components to each other, bringing thethrough-holes of both connection members face to face with each other,and sliding both connection members in a direction of the center axis ofthe optical fibers along the rodlike coupling member guided by theguide, so that the optical fibers are connected in the through-hole ofone connection member.

In the above-mentioned case, the optical fibers inserted to thethrough-holes of the connection member may be fixed to the plug by anadhesive. Further, the above-mentioned two optical fiber connectioncomponents may be attached to an adapter so as to bring thethrough-holes of the connection members face to face with each other.

The optical fiber connection structure according to the presentinvention is characterized in that it is connected by theabove-mentioned connecting method. Namely, it has a structure whichcomprises two optical fiber connection components composed each of aconnection member having one or a plurality of through-holes for opticalfibers provided with guides for rodlike coupling member at or near bothside edges, rodlike coupling members, and a turned square U-shaped plugshaving a through-hole(s) or a groove(s) for inserting an opticalfiber(s) and guide holes for rodlike coupling members on the bottom ofthe concavity of square U-shape, and optical fibers inserted into thethrough-holes of the connection members of said two optical fiberconnection components, wherein said connection member is arrangedslidably in the plug by being installed in the concavity of squareU-shape of said plug by means of the rodlike coupling members insertedin said plug, and said structure being formed by opposing two opticalfiber connection components in such a state that the optical fibers areinserted respectively in said through-holes for the optical fibers,bringing the through-holes of both connection members face to face witheach other, and sliding said connection members in a direction of thecenter axis of the optical fibers along the rodlike coupling membersguided by the guides, so that the optical fibers are connected in thethrough-hole of one connection member. In this case, the optical fiberconnection components may be attached to an adapter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plane view of an exemplary optical fiber connectioncomponent according to the present invention.

FIG. 2 shows a sectional view of the connection member in A-A line ofFIG. 1 and a sectional view of the plug in B-B line of FIG. 1.

FIG. 3 is a cross sectional view of another exemplary connection memberof the optical fiber connection component according to the presentinvention.

FIG. 4 is a plane view of another exemplary optical fiber connectioncomponent according to the present invention.

FIG. 5 is a perspective view of another exemplary optical fiberconnection component according to the present invention.

FIG. 6 is a plane view of a further exemplary optical fiber connectioncomponent according to the present invention.

FIG. 7 is a cross sectional view of another exemplary plug used for theoptical fiber connection component according to the present invention.

FIG. 8 is a flow chart illustrating an exemplary connecting methodaccording to the present invention.

FIG. 9 is a flow chart illustrating another exemplary connecting methodaccording to the present invention.

FIG. 10 is a plane view of an exemplary optical fiber connectionstructure according to the present invention.

FIG. 11 is a plane view of another exemplary optical fiber connectionstructure according to the present invention.

FIG. 12 is a plane view of the optical fiber connection component ofExample 1.

FIG. 13 is a view illustrating size of the plug in Example 1.

FIG. 14 is a view illustrating size of the connection member in Example1.

FIG. 15 is a flow chart illustrating the method of connecting opticalfibers in Example 1.

FIG. 16 is a plane view of the optical fiber connection component ofExample 2.

FIG. 17 is a view illustrating size of the connection member in Example2.

FIG. 18 is a flow chart illustrating the method of connecting opticalfibers in Example 2.

FIG. 19 is a plane view of the optical fiber connection component ofExample 3.

FIG. 20 is a view illustrating size of the plug in Example 3.

FIG. 21 is a flow chart illustrating the method of connecting opticalfibers in Example 3.

FIG. 22 is a perspective view of the adapter used in Example 4.

FIG. 23 is a flow chart illustrating the method of connecting opticalfibers in Example 4.

EXPLANATION OF SYMBOLS

1 a and 1 b . . . optical fiber connection component, 10, 10′, 10 a and10 b . . . connection member, 11 and 12 . . . guide hole, 13 . . .through-hole, 15 and 16 . . . projection, 20, 20 a and 20 b . . . plug,21 and 22 . . . guide hole, 23 . . . hole (for fixing), 24 . . . groove,28 . . . adhesive, 29 . . . cover plate, 31 and 32 . . . guide pin, 41 .. . optical fiber, 51 . . . adapter, 52 . . . latch.

BEST MODE FOR CARRYING OUT THE INVENTION

The embodiments of the present invention will hereinafter be describedwith reference to the accompanying drawings.

FIG. 1 is a plane view of an exemplary optical fiber connectioncomponent according to the present invention, FIG. 2(a) is a sectionalview of the connection member in A-A line of FIG. 1 and FIG. 2(b) is asectional view of the plug in B-B line of FIG. 1. In the drawingshereinafter, the optical fiber connection component shows the state thatone or more optical fibers have been inserted in the optical fiberconnection component. In FIGS. 1 and 2, a connection member 10 has athrough-hole 13 for inserting an optical fiber and is provided withguide holes for rodlike coupling members as the guides at or near bothside edges. Namely the connection member is provided with through-holesas the guide holes 11 and 12 for inserting guide pins 31 and 32. A plug20 has guide holes 21 and 22 for inserting guide pins 31 and 32 and ahole (fixing hole) 23 for inserting an optical fiber. The guide pins 31and 32 are inserted into the guide holes 21 and 22 of the plug so as topenetrate them, and ends of the guide pins are inserted to the guideholes 11 and 12 of the connection member 10. Thus the connection member10 is integrated in the plug 20 slidably by means of the guide pins 31and 32.

FIG. 3 is a cross sectional view of another exemplary connection member.The connection member 10, which is provided with a lot of through-holes13 in a row so that a lot of optical fibers can be connectedsimultaneously, is arranged slidably in the plug in the same manner asdescribed above.

FIG. 4 is a plane view of another exemplary optical fiber connectioncomponent according to the present invention. In this case, since a plug20 is provided with two pairs of guide holes (through-holes forinserting each a guide pin), two connection members 10 and 10′ arearranged slidably in the plug by means of guide pins inserted in saidplug.

FIG. 5 is a perspective view of another exemplary optical fiberconnection component according to the present invention. In this case,two connection members 10 and 10′ are arranged slidably in a plug 20 insuch a state that they are piled up in a perpendicular direction.

FIG. 6 is a plane view of a further exemplary optical fiber connectioncomponent according to the present invention. In this case, the opticalfiber connection component has a structure that a plug 20 hasprojections 25 and 26, and a connection member 10 has also projections15 and 16, whereby the projections are engaged with each other so thatthe connection member 10 is prevented to separate from the plug 20.Namely, the connection member 10 is arranged in the plug 20 byinstalling guide pins in such a manner that projections 15 and 16 of theconnection member engage with projections 25 and 26 of the plugrespectively.

FIG. 7 is a cross sectional view of another exemplary plug used in theoptical fiber connection component according to the present invention.In FIG. 7(a), the plug is provided with a groove 24 for inserting anoptical fiber 41, and in FIG. 7(b), a cover plate 29 having a projectionfor inserting in the groove is provided over the groove so as to fix theoptical fiber. The groove may be filled with an adhesive 28 for fixingthe optical fiber.

No particular limitation is imposed on material of the plug so far as itcan support the optical fiber and the connection member and can keeptheir shape. The material can be suitably chosen for use depending onapplication purpose, the kind of optical fibers, and installationenvironment. However, glass, plastic, ceramic, etc. are preferred touse. Furthermore, the plug may have a groove(s) as described above.

The connection member is suitably chosen for use depending on the kindof used optical fibers and an installation environment. However, theconnection member using a glass capillary, plastic capillary, metalliccapillary or ceramic capillary is preferred to use. Furthermore, it maybe composed of several kinds of composite materials. For example, aconnection member in which a glass capillary is arranged on a plastic orglass member having a V-shaped groove and metal tubes are provided asguide hole, which are fixed by a fixing member, can be used. Noparticular limitation is imposed on the number of the through-hole orthe guide hole for optical fiber prepared in the connection member sofar as the connection member can hold its mechanical strength, itsaccurate position and hole shape. For example, as illustrated in FIG. 3,a connection member in which a lot of through-holes are provided in arow so as to be capable of simultaneous connection of multi-core opticalfibers can be used. It is also possible to provide the through-holesmore than the number of optical fibers to be connected for maintenance.The shape of the through-hole provided in the connection member issuitably selected depending on the cross-sectional form of used opticalfibers. For example, a through-hole which is circular, triangular orrectangular in cross section is preferably used when cylindrical opticalfibers are connected with each other. Incidentally, it is possible touse a connection member which is prepared by mounting a flat plate on anupper face of an aligning member having a V-shaped groove, therebyforming a through-hole triangular in cross section. A through-hole whoseinner diameter is the largest at the edges thereof and is the smallestat the central part is preferred so as to make insertion of the opticalfiber easier. For example, those beveled or shaped in a conical form atthe end surfaces thereof are preferably used. Incidentally, noparticular limitation is imposed on the external form of the connectionmember.

As the rodlike coupling member, a cylindrical rod, triangular rod,tetragonal (polygonal) rod, or oval rod can be used. However, thecylindrical rod is particularly preferred to use because of easyarrangement and fabrication. As the cylindrical rod, for example, aguide pin can be used. No limitation is imposed on the form of the guidepin so far as it can be inserted in the guide hole for positioning theconnection member. For example, it is possible to use a guide pin whichhas a form different from that of the guide hole. Incidentally, nolimitation is imposed on the number of the guide pins and of the guideholes.

The optical fibers used in the optical fiber connection componentaccording to the present invention is suitably chosen for use dependingon the application purposes, and, for example, single mode opticalfibers and multi-mode optical fibers made of quartz or plastics can besuitably used.

Next, the optical fiber connecting method according to the presentinvention will be illustrated in reference to the drawings.

FIG. 8 is a flow chart illustrating an exemplary connecting methodaccording to the present invention.

As illustrated in FIG. 1 and FIG. 2, an optical fiber 41 is insertedinto a through-hole 13 of a connection member 10 and the optical fiberis then inserted into a hole 23 of a plug 20 to fix permanently ortemporarily. The connection member 10 is installed in the plug 20 byinserting guide pins 31 and 32 respectively into guide holes 11 and 12of the connection member 10 and guide holes 21 and 22 of the plug 20 sothat the connection member 10 and the plug 20 integrate to form anoptical fiber connection component into which an optical fiber isinserted. Thus the connection member is fixed to the plug in a statethat the connection member is slidable in only the direction of thecenter axis of the optical fiber to result in no damage of the opticalfiber. Namely, the optical fiber is not damaged at the edge of theconnection member upon carrying the connection member.

Another optical fiber connection component is provided by the samemanner as described above. Thereafter, both optical fiber connectioncomponents 1 a and 1 b are opposed to each other so that the connectionmember 10 a of the optical fiber connection component 1 a and theconnection member 10 b of the optical fiber connection component 1 b arebrought face to face with each other, as illustrated in FIG. 8(a). Twoconnection members 10 a and 10 b are then allowed to simultaneouslyslide in one direction (right direction in the drawing) along the guidepins, whereby the connection members are arranged and the optical fibers41 a and 41 b fixed permanently or temporarily to the plugs 20 a and 20b are connected inside the through-hole of the connection member 10 a(FIG. 8(b)). Alternatively, two connection members are first fixed toeach other by guide pins by pushing each guide pin which has beeninserted in the guide hole of one connection member in the guide hole ofthe other connection member, and the two connection members are thenallowed to slide in one direction. As mentioned above, since thethrough-holes of the connection members are aligned, the optical fiberinserted in the through-hole can be inserted easy into the through-holeof the other connection member without causing damages.

FIG. 9 is a flow chart illustrating another exemplary connecting methodaccording to the present invention. In this case, one of guide pins (31a) penetrates the connection member 10 a and the other guide pin 32 bpenetrates the connection member 10 b (FIG. 9(a)). These two connectionmembers are opposed to each other, and the projecting guide pins areinserted into the respective guide hole of the opposed other connectionmember so that the two connection members are arranged and brought faceto face with each other (FIG. 9(b)). The two connection members 10 a and10 b are then allowed to simultaneously slide in one direction (rightdirection in the drawing) along the guide pins. Thus a connectionstructure wherein the optical fibers 41 a and 41 b are connected insidethe through-hole of the connection member 10 a is obtained (FIG. 9(c)).According to the above-mentioned structure that the two optical fibersare inserted in one through-hole, there is no change in positionaccuracy of ends of the optical fibers, even if the through-hole shiftsby thermal expansion, etc. Furthermore, in case of connecting multi-coreoptical fibers, connection of the fibers can be stabilized, and there islittle variation in the connection loss among every pairs of opticalfibers.

In the above mentioned case of the present invention, the optical fibersmay be connected with each other by fixing the optical fiber to eachplug so that the end of the optical fiber is located inside theconnection component a few microns to several 10 microns apart from theend of the plug, and applying a refractive index matching agent betweenthe ends of the fibers. In case that the plugs are brought face to facewith each other, it is only necessary to adjust the axial direction ofthe optical fibers, since the distance between optical fibers does notchange by repeated operations for connection, and then stabilizedconnection can be repeatedly conducted. Further, since adjustment of adistance between edges of each pair of fibers to be connected is notrequired, stabilized connection can be obtained, when the optical fiberis fixed to the plug. Regarding the refractive index matching agent, itis possible to select depending on refractive index and material of theoptical fiber. For example, silicone oil, silicone grease, etc. arepreferably used. Moreover, when the optical fibers are fixed temporarilyto each plug, it is possible to bring the optical fibers face to facewith each other by pushing one or both optical fibers so as to moveminutely, after the ends of the optical fibers are aligned.

In the optical fiber connecting method according to the presentinvention, the connection members 10 a and 10 b may be brought face toface with each other in such a state that the plugs 20 a and 20 b areopposed at regular intervals without contacting the end surface of theplug 20 a with the end surface of the plug 20 b, as illustrated in FIG.10. In such a case, the optical fibers may be connected by approachingthe end surfaces of the plugs each other so as to bringing the opticalfibers face to face with each other.

FIG. 11 is a plane view of another exemplary optical fiber connectionstructure according to the present invention. In case of this drawing,the connection structure has two pairs of connection members installedin each plug, which can be formed by providing two optical fiberconnection components into which an optical fiber is inserted asillustrated in FIG. 4 and connecting the optical fibers as shown in FIG.8.

An optical fiber connection structure in which two connection membersare piled up in a perpendicular direction can be similarly formed usingoptical fiber connection components as illustrated in FIG. 5. Moreover,an optical fiber connection structure may be formed using an integratedplug which is prepared by fixing plural plugs arranged in a row or piledup.

No particular limitation is not imposed on the method of fixing theoptical fiber(s) to the plug so far as the optical fibers are fixed tothe plug strongly enough not to move in the end direction, and theconnecting method may be suitably chosen for use depending on theapplication purposes. An adhesive may be applied to the holes or groovesfor fixation. Any adhesives may be used, if stress strain is not appliedon the optical fiber by adhesion. For example, various kinds of pressuresensitive adhesives, thermoplastic adhesives, thermosetting adhesives,ultraviolet ray (UV) hardening adhesives of urethane, acryl, epoxy,nylon, phenol, polyimide, vinyl, silicone, rubber, fluorinated epoxy,fluorinated acryl and fluorinated polyimide types can be used. The UVhardening adhesives and thermoplastic adhesives are preferably usedbecause of easy handling.

In a method of fixing temporarily, the optical fiber is fixed to theplug with an adhesive which is easily transformed such as rubber typeadhesive, etc. Alternatively, the optical fiber is inserted in athrough-hole of the plug and a member for temporarily fixing is fixed tothe plug by means of a spring or an elastomer so that the optical fibermoves in the axial direction by pressing.

EXAMPLE

The present invention will hereafter be described in detail by thefollowing examples. However, the present invention is not limited tothese examples.

Example 1

In order to fabricate an optical fiber connection component asillustrated in FIG. 12, two plugs as illustrated in FIG. 13 and twoconnection members having a through-hole as illustrated in FIG. 14 weremade of an acrylic resin. Each of them had the size of a=14 mm, b=20 mm,c=10 mm, d=15 mm, e=2 mm, f=6 mm, g=2 mm, h=4 mm, i=2 mm, j=0.5 mm,k=2.3 mm, l=6 mm, m=1 mm, n=4 mm, and o=10 mm. The diameter of guidehole was 1 mm and the diameter of the through-hole of the connectionmember was 0.126 mm. Coat of an optical fiber (product of The FurukawaElectric Co., Ltd.; diameter: 250 μm) was then removed by 20 mm from anend to expose a cladding of the optical fiber. The cladding and core ofthe optical fiber were cut at a portion 5 mm away from the end to adjustthe length of the exposed cladding to 15 mm. The connection member wasmounted on the plug by inserting guide pins in the plug, inserting theoptical fiber into a hole for fixing the optical fiber and then into athrough-hole of the connection member, and inserting the guide pins intoeach guide hole of the connection member. After the optical fiber wasarranged so that the end of the cladding was located to the edge of theplug, the optical fiber was fixed to the plug at the center of the holefor fixing the optical fiber by means of an epoxy adhesive (EP-007;product of Cemedine Co., Ltd.). The connection member was arranged sothat the end of the cladding was located to the edge of the connectionmember, thereby completing an optical fiber connection component.

The optical fibers were connected by a method illustrated in FIG. 15.First, the thus obtained two optical fiber connection components werebrought face to face with each other (FIG. 15(a)). Two guide pins of theoptical fiber connection component in the left hand were pushedrightward to move 2 mm so that the guide pins were located inside theoptical fiber connection component in the right hand (FIG. 15(b)).Thereafter, the two connection members were allowed to slide 2 mmleftward simultaneously, thereby completing the connection of theoptical fibers (FIG. 15(c)).

In the obtained optical fiber connection structure, the optical fiberswere prevented from being damaged upon connecting them, because eachcladding which was easily damaged was inserted in the through-hole ofthe connection member. Moreover, connection between the optical fiberswas feasible with ease.

Thereafter, a connection loss was measured at the coupling point of theoptical fibers and found to be 0.7 dB or less. The connection structurewas thus sufficiently usable as an optical connection structure.

Example 2

In order to fabricate an optical fiber connection component asillustrated in FIG. 16, two plugs 20 as illustrated in FIG. 13 and twoconnection members 10 having four through-holes as illustrated in FIG.17 were made of an acrylic resin. Each of them had the size of a=14 mm,b=20 mm, c=10 mm, d=15 mm, e=2 mm, f=6 mm, g=2 mm, h=4 mm, i=2 mm, j=0.5mm, k=1.3 mm, l=6 mm, m=1 mm, n=4 mm, o=10 mm and p=0.25 mm. Thediameter of the guide holes was 1 mm and the diameter of the fourthrough-holes of the connection member was 0.126 mm. Coats of eightoptical fibers (products of The Furukawa Electric Co., Ltd.; diameter:250 μm) were then removed by 20 mm from their ends to expose claddingsof the optical fibers. The claddings and cores of the optical fiberswere cut at a portion 5 mm away from an end to adjust the length of theexposed claddings to 15 mm. The connection member was installed in theplug by inserting two guide pins in the plug, inserting four opticalfibers into each hole for fixing the optical fiber and then into eachthrough-hole of the connection member, and inserting the guide pins intoeach guide hole of the connection member. After the optical fibers werearranged so that the ends of the claddings were located to the edge ofthe plug, the four optical fibers were fixed to the plug at the centerof the holes for fixing the optical fiber by means of an epoxy adhesive(EP-007; product of Cemedine Co., Ltd.). The connection member wasarranged so that the ends of each cladding were located to the edge ofthe connection member, thereby completing an optical fiber connectioncomponent into which optical fibers were inserted.

The optical fibers were connected by the method illustrated in FIG. 18.First, the thus obtained two optical fiber connection components werebrought face to face with each other (FIG. 18(a)). Two guide pins of theoptical fiber connection component in the left hand were pushedrightward to move 2 mm so that the guide pins were located inside theoptical fiber connection component in the right hand (FIG. 18(b)).Thereafter, the two connection members were allowed to simultaneouslyslide 2 mm leftward, thereby completing the connection of the opticalfibers (FIG. 18(c)).

In the obtained optical fiber connection structure, the optical fiberswere prevented from being damaged upon connecting them, because thecladdings which were easily damaged were inserted in the through-holesof the connection members. Moreover, connection between the opticalfibers was feasible with ease.

Thereafter, a connection loss was measured at the junction points of theoptical fibers and found to be 0.7 dB or less. The connection structurewas thus sufficiently usable as an optical connection structure.

Example 3

In order to fabricate an optical fiber connection component asillustrated in FIG. 19, two plugs as illustrated in FIG. 20 and twoconnection members 10 having four through-holes as illustrated in FIG.17 were made of an acrylic resin. Each of them had the size of a=24 mm,b=20 mm, c=20 mm, d=15 mm, e=2 mm, f=6 mm, g=2 mm, h=4 mm, i=2 mm, j=0.5mm, k=2.3 mm, l=6 mm, m=1 mm, n=4 mm, o=10 mm and p=0.25 mm. Thediameter of the guide holes was 1 mm and the diameter of the fourthrough-holes of the connection member was 0.126 mm. Coats of 16 opticalfibers (products of The Furukawa Electric Co., Ltd.; diameter: 250 μm)were then removed by 20 mm from their ends to expose claddings of theoptical fibers. The claddings and cores of the optical fibers were cutat a portion 5 mm away from the end to adjust the length of the exposedcladdings to 15 mm. The connection member was installed in the plug byinserting four guide pins in the plug, inserting eight optical fibersinto each hole for fixing the optical fibers and then into eachthrough-hole of the connection member, and inserting the guide pins intoeach guide hole of the connection member. After the optical fibers werearranged so that the ends of the claddings were located to the edge ofthe plug, the eight optical fibers were fixed to the plug at the centerof the holes for fixing the optical fiber by means of an epoxy adhesive(EP-007; product of Cemedine Co., Ltd.). The connection member wasarranged so that the ends of the claddings were located to the edge ofthe connection member, thereby completing an optical fiber connectioncomponent into which optical fibers had been inserted.

The optical fibers were connected by the method illustrated in FIG. 21.First, the thus obtained two optical fiber connection components werebrought face to face with each other (FIG. 21(a)). Four guide pins ofthe optical fiber connection component in the left hand were pushedrightward to move 2 mm so that the four guide pins were located insidethe optical fiber connection component in the right hand (FIG. 21(b)).Thereafter, the two connection members were allowed to simultaneouslyslide 2 mm leftward, thereby completing the connection of the opticalfibers (FIG. 21(c)).

In the obtained optical fiber connection structure, the optical fiberswere prevented from being damaged upon connecting them, because thecladdings which were easily damaged were inserted in the through-holesof the connection members. Moreover, connection between the opticalfibers was feasible with ease.

Thereafter, a connection loss was measured at the coupling points of theoptical fibers and found to be 0.7 dB or less. The connection structurewas thus sufficiently usable as an optical connection structure.

Example 4

This example illustrates a case of connecting optical fibers using anadapter having a structure shown in FIG. 22. As illustrated in FIG. 22,the adapter 51 was provided with latches 52 in the centers of sideboards so as to fix two optical fiber connection components in whichoptical fibers had been inserted into through-holes.

Two optical fiber connection components were prepared in the similarmanner to Example 2 by inserting four optical fibers into each hole forfixing the optical fiber of the plug 20, inserting claddings into eachthrough-hole of the connection member 10, and inserting guide pins 31and 32 into each guide hole of the connection member. Thus resultantconnection components were attached and fixed to the above-mentionedadapter (FIG. 23(a)). Two guide pins of the optical fiber connectioncomponent in the left hand were then pushed rightward to move 2 mm sothat the two guide pins were located inside the optical fiber connectioncomponent in the right hand (FIG. 23(b)). Thereafter, the two connectionmembers were allowed to simultaneously slide 2 mm leftward, therebycompleting the connection of the optical fibers (FIG. 23(c)).

In the obtained optical fiber connection structure, the optical fiberswere prevented from being damaged upon connecting them, because thecladdings which would be easily damaged were inserted in thethrough-holes of the connection member. Moreover, connection between theoptical fibers was more feasible with ease, because plugs, to whichoptical fibers were fixed, were fixed to the adapter so that the opposedstate of plugs was kept stable. Furthermore, the distance betweenoptical fibers was stabilized, and the connection of the optical fiberswas kept stable.

Thereafter, a connection loss was measured at the coupling points of theoptical fibers and found to be 0.7 dB or less. The connection structurewas thus sufficiently usable as an optical connection structure.

INDUSTRIAL AVAILABILITY

Since the optical fiber connection component according to the presentinvention has above-mentioned constitution, adjusting the distancesbetween ends of each optical fiber pair can be easily conducted uponaligning the optical fibers and, particularly, claddings of the opticalfibers, from which a coating has been removed when it is applied for theoptical connection between optical fibers led out of ends thereof suchas optical elements, optical circuit packages, optical circuit devices,etc. And optical fibers are prevented from being damaged upon carryingor connecting them, because the connection member is arranged in theplug. In addition, connecting workability can be improved, because partsnecessary for connection are not dispersed or lost or its position doesnot shift. Further, it becomes possible to decrease the number of partsfor connection since the connection members can be stably positioned toeach other. Accordingly, connection of optical fibers can be conductedat low cost because of using only few parts. Furthermore, the opticalfiber connection structure according to the present invention can beapplied for multi-core connection. Namely, position of each fiber is notaffected, and dispersion of the connection loss at the junction pointsof the optical fibers is narrow, and so multi-core connection can beeasily conducted.

1. An optical fiber connection component which comprises a connectionmember having one or a plurality of through-holes for optical fibersprovided with guides for rodlike coupling member at or near both sideedges, rodlike coupling members, and a turned square U-shaped plughaving a through-hole(s) or a groove(s) for inserting an opticalfiber(s) and guide holes for rodlike coupling members on the bottom ofthe concavity of square U-shape, wherein said connection member isarranged slidably in said plug by being installed in the concavity ofsquare U-shape of said plug by means of the rodlike coupling memberinserted in the plug:
 2. The optical fiber connection componentaccording to claim 1 wherein said guide is a through-hole or a groove.3. The optical fiber connection component according to claim 1 whereinsaid rodlike coupling member is cylindrical.
 4. The optical fiberconnection component according to claim 1 wherein two or more connectionmembers are arranged in the plug.
 5. (canceled)
 6. An optical fiberconnecting method which comprises opposing two optical fiber connectioncomponents comprising each a connection member having one or a pluralityof through-holes for optical fiber provided with guides for rodlikecoupling members at or near both side edges, rodlike coupling members,and a turned square U-shaped plug having a through-hole(s) or agroove(s) for inserting an optical fiber(s) and guide holes for rodlikecoupling members on the bottom of the concavity of square U-shape,wherein said connection member is arranged slidably in said plug bybeing installed in the concavity of square U-shape of said plug by meansof the rodlike coupling members inserted in said plug in such a statethat the optical fibers are inserted respectively in said through-holesfor optical fiber, bringing the through-holes of both connection membersface to face with each other, and sliding said connection members in adirection of the center axis of the optical fibers along the rodlikecoupling members guided by the guides, so that the optical fibers areconnected in the through-hole of one connection member.
 7. The opticalfiber connecting method according to claim 6 wherein optical fibersinserted respectively in the through-holes of the connection members arefixed to the plugs by an adhesive.
 8. The optical fiber connectingmethod according to claim 6 which comprises attaching said two opticalfiber connection components to an adapter and bringing the through-holesof them face to face each other.
 9. An optical fiber connectionstructure which is formed by opposing two optical fiber connectioncomponents comprising each a connection member having one or a pluralityof through-holes for optical fiber provided with guides for rodlikecoupling member at or near both side edges, rodlike coupling members,and a turned square U-shaped plug having a through-hole(s) or agroove(s) for inserting an optical fiber(s) and guide holes for rodlikecoupling members on the bottom of the concavity of square U-shape,wherein said connection member is arranged slidably in said plug bybeing installed in the concavity of square U-shape of said plug by meansof the rodlike coupling members inserted in said plug, in such a statethat the optical fibers are inserted respectively in said through-holesfor the optical fibers, bringing the through-holes of both connectionmembers face to face with each other, and sliding said connectionmembers in a direction of the center axis of the optical fibers alongthe rodlike coupling members guided by the guides, so that the opticalfibers are connected in the through-hole of one connection member. 10.The optical fiber connection structure according to claim 9 wherein arefractive index matching agent is used for connecting the opticalfibers.
 11. The optical fiber connection structure according to claim 9wherein the optical fiber connection component is fixed to an adapter.